Aromatic polysulfone and aromatic polysulfone composition

ABSTRACT

The invention provides an aromatic polysulfone including an aromatic polysulfone having at least one highly polar functional group at its terminus, wherein in the aromatic polysulfone, an area of a signal attributed to the aromatic polysulfone having a highly polar functional group with respect to a total area of all signals attributed to the aromatic polysulfone in a chromatogram obtained by measurement through a gel permeation chromatography method under the following conditions is 0.1% or more and 11% or less, wherein the sample injection volume is 5 μL, column is “Shodex KF-803” manufactured by Showa Denko K.K., column temperature is 40° C., eluent is N,N-dimethylformamide, eluent flow rate is 0.5 mL/min, detector is ultraviolet-visible spectrophotometer (UV), and detection wavelength is 277 nm.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a Section 371 of International Application No.PCT/JP2017/022822, filed Jun. 21, 2017, which was published in theJapanese language on Dec. 28, 2017 under International Publication No.WO 2017/221972 A1, and claims priority under 35 U.S.C. § 119(b) toJapanese Application No. 2016-125965 filed Jun. 24, 2016, thedisclosures of which are incorporated herein by reference in theirentirety.

TECHNICAL FIELD

The present invention relates to an aromatic polysulfone and an aromaticpolysulfone composition.

Priority is claimed on Japanese Patent Application No. 2016425965, filedJun. 24, 2016, the content of which is incorporated herein by reference.

Since aromatic polysulfones are one type of amorphous thermoplasticresins and are excellent in heat resistance, mechanical properties andtransparency, they are used for various applications, such as parts ofelectronic devices, as forming materials of molded articles and films.An aromatic polysulfone is usually produced by subjecting an aromaticdihalogenosulfone compound and an aromatic dihydroxy compound to apolycondensation reaction in the presence of a base and a reactionsolvent (see, for example, Patent Document 1).

As one method for producing a film using an aromatic polysulfone as aforming material, a solution casting method can be mentioned. Thesolution casting method is widely known because it can obtain a filmwith less foreign matter and excellent thickness accuracy and surfacesmoothness. In the solution casting method, first, a solution in whichan aromatic polysulfone is dissolved (hereinafter sometimes referred toas “aromatic polysulfone solution”) is extruded with a die, cast on ametal substrate, and dried to thereby prepare a coating film.Subsequently, this coating film is peeled off from the metal substrate,whereby a film is obtained. However, when peeling the coating film fromthe metal substrate, if the adhesive force between the coating film andthe metal substrate is too strong, the film may be elongated orruptured.

With respect to this problem, for example, a method is known in which apredetermined amount of solvent is left when an aromatic polysulfonesolution is dried, and the film after peeling is dried again. However, afilm in which a predetermined amount of solvent remains is inferior inmechanical strength, and elongation of the film at the time of peelingcannot be sufficiently suppressed, so that the thickness of the film maybe uneven and the orientation may be disturbed.

Further, if it takes time for the peeling step in order to avoidelongation of the film, productivity may decrease.

Furthermore, as another method, a method of adding a surfactant to anaromatic polysulfone solution is known. However, although elongation andrupture of the film can be reduced, the surfactant bleeds out in thefilm after peeling, which may adversely affect the performance of thefilm see Patent Document 2).

Therefore, an aromatic polysulfone excellent in releasability and anaromatic polysulfone composition containing this aromatic polysulfonehave been desired.

CITATION LIST Patent Documents

[Patent Document 1] Published Japanese Translation No. 2012-509375 ofthe PCT International Publication

[Patent Document 2] Japanese Unexamined Patent Application, FirstPublication No. Hei 9-216241

SUMMARY OF INVENTION Technical Problem

The present invention has been made in view of such circumstances,object of providing an aromatic polysulfone having excellentreleasability. In addition, another object of the present invention isto provide an aromatic polysulfone composition containing this aromaticpolysulfone.

Solution to Problem

In order to solve the above-mentioned problems, one aspect of thepresent invention provides an aromatic polysulfone in which an aromaticpolysulfone having at least one highly polar functional group at itsterminal (hereinafter sometimes referred to as an aromatic polysulfone,having a highly polar functional group) is contained, and ratio of thearomatic polysulfone having a highly polar functional group with respectto the combined total of all the aromatic polysulfones is 0.1% by massor more and 11% by mass or less.

That is, in one aspect of the present invention, an aromatic polysulfoneis provided, in which a ratio obtained by dividing an area of signalattributed to an aromatic polysulfone having a highly polar functionalgroup with a total area of all the signals attributed to the aromaticpolysulfone is 0.1% by mass or more tend 11% by as or less achromatogram obtained when measured by a gel permeation chromatography(GPC) method under the following conditions.

[Conditions]

Sample injection volume: 5 μL

Column: “Shodex KF-803” manufactured by Showa Denko K.K.

Column temperature: 40° C.

Eluent: N,N-dimethylformamide

Eluent flow rate: 0.5 mL/min

Detector: ultraviolet-visible spectrophotometer (UV)

Detection wavelength: 277 nm

In one aspect of the present invention, it is preferable to have arepeating unit represented by a formula (1).-Ph¹-SO₂-Ph²-O—  (1)

[In the formula (1), Ph¹ and Ph² each independently represent aphenylene group; and one or a more hydrogen atoms in the phenylene groupmay be each independently substituted with an alkyl group, an aryl groupor a halogen atom.]

In one aspect of the present invention, it is preferable to have 0.5 to10 phenolic hydroxyl groups per 100 repeating units represented by theformulas).

One aspect of the present invention provides an aromatic polysulfonecomposition containing the above aromatic polysulfone.

In one aspect of the present invention, it is preferable to furtherinclude a filler.

Advantageous Effects of Invention

According to one aspect of the present invention, an aromaticpolysulfone having excellent releasability is provided. In addition, anaromatic polysulfone composition containing this aromatic polysulfone isalso provided.

That is, the present relates to the following.

[1] An aromatic polysulfone which is an aromatic polysulfone containingan aromatic polysulfone having at least one highly polar functionalgroup at its terminal,

wherein in the aforementioned aromatic polysulfone, an area of a signalattributed to the aforementioned aromatic polysulfone having a highlypolar functional group with respect to a total area of all signalsattributed to the aforementioned aromatic polysulfone in a chromatogramobtained by measurement through a gel permeation chromatography methodunder the following conditions is 0.1% or more and 11% or less,

[Conditions]

Sample injection volume: 5 μL

Column: “Shodex KE-803” manufactured by Showa Denko K.K.

Column temperature: 40° C.

Eluent: N,N-dimethylformamide

Eluent flow rate: 0.5 mL/min

Detector: ultraviolet-visible spectrophotometer (UV)

Detection wavelength: 277 nm.

[2] The aromatic polysulfone according to [1], which has a repeatingunit represented by a formula (1),-Ph¹-SO₂-Ph²-O—  (1)

[In the formula (1), Ph¹ and Ph² each independently represent aphenylene group, and one or more hydrogen atoms in the aforementionedphenylene group may be each independently substituted with an alkylgroup, an aryl group or a halogen atom.]

[3] The aromatic polysulfone according to [2], which has 0.5 to 10phenolic hydroxyl groups per 100 repeating units represented by theaforementioned formula (1).

[4] An aromatic polysulfone composition including the aromaticpolysulfone according to any one of [1] to [3].

[5] The aromatic polysulfone composition according to [4], furtherincluding a filler.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a chromatogram obtained when measured by a GPC method,

FIG. 2 is a chromatogram of Production Example 1 obtained by a GPCmethod (content measurement).

DESCRIPTION OF EMBODIMENTS

<Aromatic Polysulfone>

Typically, an aromatic polysulfone of the present embodiment is a resinincluding a repeating unit that contains a divalent aromatic group (aresidue formed by removing, from an aromatic compound, two hydrogenatoms bonded to its aromatic ring), a sulfonyl group (—SO₂—) and anoxygen atom.

Further, the aromatic polysulfone preferably has a repeating unitrepresented by a formula (1) (hereinafter may be referred to as“repeating unit (1)” in some cases)

In particular, an aromatic polysulfone having the repeating unit (1) isreferred to as an aromatic polyether sulfone. Furthermore, at least oneother repeating unit such as a repeating unit represented by a formula.(2) (hereinafter referred to as “repeating unit (2)” in some cases) or arepeating unit represented by a formula (3) (hereinafter referred to as“repeating unit (3)” in some cases) may be contained.-Ph¹-SO₂-Ph²-O—  (1)

[In the formula (1), Ph¹ and Ph² each independently represent aphenylene group; and one or more hydrogen atoms in the aforementionedphenylene group may be each independently substituted with an alkylgroup, an aryl group or a halogen atom.]-Ph³-R-Ph⁴-O—  (2)

[In the formula (2), Ph³ and Ph⁴ each independently represent aphenylene group; one or more hydrogen atoms in the aforementionedphenylene group may be each independently substituted with an alkylgroup, an aryl group or a halogen atom; and R represents an alkylidenegroup, an oxygen atom or a sulfur atom.]—(Ph⁵)_(n)—O—  (3)

[In the formula (3), Ph⁵ represents a phenylene group; one or morehydrogen atoms in the aforementioned phenylene group array be eachindependently substituted with an alkyl group, an aryl group or ahalogen atom; n represents an integer of 1 to 3; and when n is 2 ormore, a plurality of Ph⁵ groups may be the same as or different fromeach other.]

The phenylene group represented by any one of Ph¹ to Ph⁵ may be eachindependently a p-phenylene group, an m-phenylene group or ano-phenylene group, but it is preferably a p-phenylene group,

The alkyl group which may substitute the hydrogen atom in the phenylenegroup is preferably an alkyl group having 1 to 10 carbon atoms. Examplesof the alkyl group having 1 to 10 carbon atoms include a methyl group,an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group,an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentylgroup, an n-hexyl group, an n-heptyl group, a 2-ethylhexyl group, ann-octyl group and an n-decyl group.

The aryl group which may substitute the hydrogen atom in the phenylenegroup is preferably an aryl group having 6 to 20 carbon atoms. Examplesof the aryl group having 6 to 20 carbon atoms include a phenyl group, ano-tolyl group, an m-tolyl group, a p-tolyl group, a 1-naphthyl group anda 2-naphthyl group.

Examples of the halogen atom which may substitute the hydrogen atom inthe phenylene group include a fluorine atom, a chlorine atom, a bromineatom and an iodine atom.

In the case where the hydrogen atom in the phenylene group issubstituted with these functional groups, the number thereof is eachindependently preferably 2 or less, and more preferably 1, for each ofthe phenylene groups.

The alkylidene group represented by R is preferably an alkylidene grouphaving 1 to 5 carbon atoms. Examples of the alkylidene group having 1 to5 carbon atoms include a methylene group, an ethylidene group, anisopropylidene group and a 1-butylidene group.

The aromatic polysulfone of the present embodiment preferably includes50 mol % or more, and more preferably 80 mol % or more, of the repeatingunit (1), with respect to the total amount of all the repeating unitsconstituting the aromatic polysulfone, and as the repeating unit, it isstill more preferable to substantially include only the repeating unit(1), and it is particularly preferable to include only the repeatingunit (1),

That is, the aromatic polysulfone of the present embodiment preferablyincludes 50 mol % or more and 100 mol % or less, more preferably 80 mol% or more and 100 mol % or less, and particularly preferably 100 mol %of the repeating unit (1), with respect to the total amount of all therepeating units constituting the aromatic polysulfone.

It should be noted that the aromatic polysulfone may have two or more ofthe repeating units (1) to (3) independently of each other.

Further, the aromatic polysulfone includes an aromatic polysulfonehaving at least one highly polar functional group at its terminal. Inthe present specification, “an aromatic polysulfone having at least onehighly polar functional group at its terminal” may be simply referred toas “aromatic polysulfone having a highly polar functional group”.

As one aspect, the aromatic polysulfone of the present embodiment may bea mixture of an aromatic polysulfone having a highly polar functionalgroup and an aromatic polysulfone having no highly polar functionalgroup, or may consist of only an aromatic polysulfone having a highlypolar functional group.

A “highly polar functional group” specifically means a polar functionalgroup having an acid dissociation constant smaller than that of thecarboxyl group. Examples of the highly polar functional group include asulfonic acid group (—SO₂OH), a sulfinic acid group (—SO₂H) or a saltthereof. An aromatic polysulfone containing a sulfonic acid group, asulfinic acid group or a salt thereof is produced by decomposition ofthe repeating unit (1) in the aromatic polysulfone and reaction withmoisture in the air or in the resin. Further, it can be obtained byreplacing the terminal functional group (hydroxyl group or halogen atom)of the polymer with a compound having a highly polar functional groupafter the polymerization reaction described later.

Here, the type of highly polar functional group can be identified by amatrix-assisted laser desorption ionization (sometimes abbreviated asMALDI) method after fractionating the aromatic polysulfone having ahighly polar functional group in the GPC measurement described later.

The highly polar functional group interacts with the surface of anadhesive or pressure-sensitive adhesive, or a reactive functional grouppresent on the surface to chemically or electrically couple the aromaticpolysulfone to the surface. Therefore, when an aromatic polysulfonecontains too many highly polar functional groups, releasability of thearomatic polysulfone may decrease.

In the aromatic polysulfone of the present embodiment, the ratio of thearomatic polysulfone having a highly polar functional group with respectto the combined total of all the aromatic polysulfones (that is, thecontent ratio of the aromatic polysulfone having a highly polarfunctional group with respect to the total mass of aromaticpolysulfones) is 0.1% by mass or more and 11% by mass or less. Further,the ratio may be 8% by mass or more and 11% by mass or less. When theratio of the aromatic polysulfone having a highly polar functional groupis within the above range, the releasability of the aromatic polysulfonecan be improved.

Here, the content ratio of the aromatic polysulfone having a highlypolar functional group is measured by a gel permeation chromatography(GPC) method. More specifically, in a chromatogram obtained whenmeasured by the GPC method under the following conditions (measurementconditions and analysis conditions), it is obtained by dividing an areaof a signal attributed to the aromatic polysulfone having a highly polarfunctional group (hereinafter referred to as “component A” in somecases) with a total area of all the signals attributed to aromaticpolysulfones.

[Measurement Conditions]

Sample injection volume: 5 μL

Column: “Shodex KF-803” manufactured by Showa Denko K.K.

Column temperature: 40° C.

Fluent: N,N-dimethylformamide

Eluent flow rate: 0.5 mL/min

Detector: ultraviolet-visible spectrophotometer (UV)

Detection wavelength: 277 nm

[Analysis Conditions]

Software: “LabSolutions” manufactured by Shimadzu Corporation

Width: 70 seconds

Slope: 1,000 uV/min

Drift: 0 uV/min

Minimum area/height: 1,000 counts

Analysis start time: 0 minutes

Analysis end time: 22 minutes

FIG. 1 is a chromatogram obtained when measured by the GPC method underthe above conditions.

The above-described “Shodex KF-803” manufactured by Showa Denko K.K. isa gel permeation chromatography column packed with a styrenedivinylbenzene copolymer resin and having an inner diameter×height of8.0 mm×300 mm, and the styrene divinylbenzene copolymer resin has aparticle size of 6 μm.

The component A shown in FIG. 1 is attributed to an aromatic polysulfonehaving a highly polar functional group. In the present embodiment, aratio obtained by dividing the area of the component A by the total areaof all the signals attributed to aromatic polysulfones corresponds to aratio of the mass of the aromatic polysulfone having a highly polarfunctional group corresponding to the component A with respect to themass of the combined total of all the aromatic polysulfones (the totalmass of aromatic polysulfones). It should be noted that since thearomatic polysulfone having at least one highly polar functional groupat its terminal and the aromatic polysulfone having no highly polarfunctional group at its terminal have the same main chain skeleton,molar extinction coefficients thereof with respect to the detectionlight (UV: 277 nm) are substantially the same. Therefore, the area ofthe detected signal corresponds to the mass.

That is, as one aspect, the aromatic polysulfone of the presentembodiment is an aromatic polysulfone containing an aromatic polysulfonehaving at least one highly polar functional group at its terminal,wherein a ratio obtained by dividing an area of a signal attributed tothe aforementioned aromatic polysulfone having a highly polar functionalgroup by a total area of all the signals attributed to theaforementioned aromatic polysulfone in a chromatogram obtained bymeasurement through a gel permeation chromatography method under theabove conditions is 0.1% or more and 11% or less. The ratio may be 8% ormore and 11% or less.

As another aspect, the aromatic polysulfone of the present embodiment isan aromatic polysulfone containing an aromatic polysulfone having atleast one highly polar functional group at its terminal, wherein an areaof a signal attributed to the aforementioned aromatic polysulfone havinga highly polar functional group with respect to a total area of allsignals attributed to the aforementioned aromatic polysulfone in achromatogram obtained by measurement through a gel permeationchromatography method under the above conditions is 0.1% or more and 11%or less, or may be 8% or more and 11% or less.

Although a solvent to which a salt such as lithium bromide is added at aconcentration of 10 mM (1 mM=1×10⁻³ mol/L) is usually used as an eluentin a GPC measurement of a polymer having a polar group, under themeasurement conditions of the present invention, an eluent containing nosuch salt is used. Since an aromatic polysulfone having a highly polarfunctional group and the stationary phase are electrically repulsed byusing an eluent containing no salt, the retention time can be madefaster for the aromatic polysulfone having a highly polar functionalgroup, as compared with aromatic polysulfones having no highly polarfunctional group. This makes it possible to separate a peak derived fromthe aromatic polysulfone having a highly polar functional group andpeaks derived from aromatic polysulfones having no highly polarfunctional group, and measurement with high reproducibility becomespossible.

When lithium bromide is added to the eluent, the component A is notidentified. In other words, when lithium bromide is not added to theeluent, the component A is identified. By not adding lithium bromide tothe eluent, the component A can be identified as a signal having aretention time faster than that of a signal attributed to an aromaticpolysulfone having no highly polar functional group at its terminal dueto an ion exclusion effect.

Here, the signal of the aromatic polysulfone having no highly polarfunctional group at its terminal can be identified by being comparedwith the retention of the aromatic polysulfone whenN,N-dimethylformamide added with 10 mM lithium bromide is used as theeluent. That is, the retention time of the aromatic polysulfones((aromatic polysulfone having at least one highly polar functional groupat its terminal)+(aromatic polysulfone having no highly polar functionalgroup at its terminal)) when N,N-dimethylformamide prepared by adding 10mM lithium bromide is used as be eluent and the retention time of thearomatic polysulfone having no highly polar functional group at itsterminal when N,N-dimethylformamide prepared without adding 10 mMlithium bromide is used as the eluent are substantially the same.Further, a signal having a retention time earlier than the of thearomatic polysulfone having no highly polar functional group at itsterminal is assigned as a signal (component A) of an aromaticpolysulfone having at least one highly polar functional group at itsterminal.

Furthermore, in the aromatic polysulfone of the present embodiment, itis preferable to include 0.5 to 10 phenolic hydroxyl groups per 100repeating units represented by the formula (1). When the number ofreactive phenolic hydroxyl groups per 100 repeating units represented bythe formula (1) is from 0.5 or more to 10 or less, the aromaticpolysulfone can be finely dispersed when alloying a thermoplastic resinor thermosetting resin with the aromatic polysulfone.

As another aspect, the number of phenolic hydroxyl groups may be 1 ormore and 2 or less, and may be 1 or more and 1.82 or less, per 100repeating units represented by the formula (1).

Here, the number (A) f phenolic hydroxyl groups per 100 repeating unitsrepresented by the formula (1) is measured by an NMR method. Morespecifically, in the ¹H-NMR measurement, it can be calculated based onthe following formula (S1) using an area (x) of a signal attributed tofour hydrogen atoms bonded to the phenol group in the repeating unit (1)and an area (y) of a signal attributed to two hydrogen atomsrespectively bonded to the carbon atom two atoms away from the phenolichydroxyl group.A=(y×100/x)×2(S1)

The measurement solvent in the ¹H-NMR measurement s not particularlylimited as long as it is a solvent capable of ¹H-NMR measurement andcapable of dissolving aromatic polysulfones, but deuterated dimethylsulfoxide or the like is preferable.

The reduced viscosity (unit: dL/g) of the aromatic polysulfone of thepresent embodiment is preferably 0.18 or more, and more preferably 0.22or more and 0.80 or less. The higher the reduced viscosity of aromaticpolysulfone, the easier it is to improve heat resistance and thestrength and rigidity when formed into a molded article, but if it istoo high, the melt temperature and melt viscosity tend to be high andthe fluidity tends to be low.

Here, the reduced viscosity is a value measured at a resin concentrationof 1.0 g/100 ml in an N,N-dimethylformamide solution at 25° C. using anOstwald type viscosity tube.

The number average molecular eight (Mn) of the aromatic polysulfone ofthe present embodiment is preferably, for example, 6,000 or more and40,000 or less.

The weight average molecular weight (Mw) of the aromatic polysulfone ofthe present embodiment is preferably, for example, 9,000 or more and90,000 or less.

The Mw/Mn value (polydispersity) of the aromatic polysulfone of thepresent embodiment is preferably 1.5 or more and 3.0 or less,

The values of Mn, Mw and Mw/Mn can be obtained by a method described in<Measurement of Mn and Mw values of aromatic polysulfones, andcalculation of Mw/Mn value> to be described later.

<Method for Producing Aromatic Polysulfone>

The aromatic polysulfone of the present embodiment can be produced byusing an aromatic dihalogenosulfone compound and an aromatic dihydroxycompound as monomers and subjecting these monomers to a polycondensationreaction in an organic solvent e presence of a base.

[Monomer]

The aromatic dihalogenosulfone compound and the aromatic dihydroxycompound correspond to the repeating unit constituting the aromaticpolysulfone. Further, the aromatic dihalogenosulfone compound may be acompound having an aromatic ring, a sulfonyl group and two halogenogroups in one molecule. Moreover, the aromatic dihydroxy compound may bea compound having an aromatic ring and two hydroxy groups in onemolecule.

For example, an aromatic polysulfone having the repeating unit (1) canbe produced by using a compound represented by a formula (4)(hereinafter may be referred to as “compound (4)” in some cases) as thearomatic dihalogenosulfone compound, and using a compound represented bya formula (5) (hereinafter may be referred to as “compound (5)” in somecases) as the aromatic dihydroxy compound.

Further, an aromatic polysulfone having the repeating unit (1) and therepeating unit (2) can be produced by using the compound (4) as thearomatic dihalogenosulfone compound and using a compound represented bya formula (6) (hereinafter may be referred to as “compound (6)” in somecases) as the aromatic dihydroxy compound.

Moreover, an aromatic polysulfone having the repeating unit (1) and therepeating unit (3) can be produced by using the compound (4) as thearomatic dihalogenosulfone compound and using a compound represented bya formula (7) (hereinafter may be referred to as “compound (7)” in somecases) as the aromatic dihydroxy compound.X¹-Ph¹-SO₂-Ph²-X²  (4)

[In the formula (4), X¹ and X² each independently represent a halogenatom; and Ph¹ and Ph² are the same as defined above.]HO-Ph¹-SO₂-Ph²-OH  (5)

[In the formula (5), Ph¹ and Ph² are the same as defined above.]HO-Ph³-R-Ph⁴-OH  (6)

[In the formula (6). Ph³, Ph⁴ and R are the same as defined above.]HO-(Ph⁵)_(n)—OH  (7)

[In the formula (7), Ph⁵ and n are the same as defined above.]

As the halogen atom represented by X¹ and X², the same halogen atomwhich may substitute the hydrogen atom in the aforementioned phenylenegroup can be mentioned.

Examples of the compound (4) include bis(4-chlorophenyl) sulfone and4-chlorophenyl-3′,4′-dichlorophenyl sulfone.

Examples of the compound (5) include bis(4-hydroxyphenyl) sulfone,bis(4-hydroxy-3,5-dimethylphenyl) sulfone andbis(4-hydroxy-3-phenylphenyl) sulfone.

Examples of the compound (6) include 2,2-bis(4-hydroxyphenyl) propane,2,2-bis(4-hydroxyphenyl) hexafluoropropane, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxy-3-methylphenyl) sulfide and bis(4-hydroxyphenyl)ether.

Examples of the compound (7) include hydroquinone, resorcin, catechol,phenylhydroquinone, 4,4′-dihydroxybiphenyl, 2,2′-dihydroxybiphenyl,3,5,3′,5′-tetramethyl-4,4′-dihydroxybiphenyl,2,2′-diphenyl-4,4′-dihydroxybiphenyl and 4,4′-dihydroxy-p-quaterphenyl.

As an example of the aromatic dihalogenosulfone compound other than thecompound (4), 4,4′-bis(4-chlorophenylsulfonyl) biphenyl can bementioned.

In the present embodiment stead of all or part of the aromaticdihalogenosulfone compound and the aromatic dihydroxy compound, acompound having a halogeno group and a hydroxy group in a molecule suchas 4-hydroxy-4′-(4-chlorophenylsulfonyl) biphenyl can also be used.

In the present embodiment, depending on the type of intended aromaticpolysulfone, any one of the aromatic dihalogenosulfone compound and thearomatic dihydroxy compound may be used alone, or two or more of themmay be used in combination.

[Base, Organic Solvent]

Polycondensation between the aromatic dihalogenosulfone compound and thearomatic dihydroxy compound is preferably carried out using an alkalimetal salt of carbonic acid as a base. Further, it is preferably carriedout in an organic solvent as a polycondensation solvent, and morepreferably carried out using an alkali metal salt of carbonic acid as abase and in an organic solvent.

The alkali metal salt of carbonic acid may be an alkali carbonate whichis a normal salt (that is, an alkali metal carbonate), or an alkalibicarbonate which is an acid salt, (that is, an alkali hydrogencarbonateor an alkali metal hydrogencarbonate), or it may be a mixture of these(an alkali carbonate and an alkali bicarbonate). As the alkalicarbonate, for example, sodium carbonate, potassium carbonate and thelike are preferable. As the alkali bicarbonate, for example, sodiumbicarbonate (also referred to as sodium hydrogen carbonate), potassiumbicarbonate (also referred to as potassium hydrogen carbonate) and thelike are preferable.

The type of the organic solvent is not particularly limited, but it ispreferably an aprotic polar solvent. Further, the boiling point of theorganic solvent is not particularly limited, but it is preferably, forexample, 100° C. or more and 400° C. or less, and more preferably 100°C. or more and 350° C. or less.

Examples of such organic solvents include sulfoxides such asdimethylsulfoxide; amides such as dimethylformamide, dimethylacetamideand N-methyl-2-pyrrolidone; sulfones such as sulfolane (also referred toas 1,1-dioxotilane), dimethylsulfone, diethylsulfone, diisopropylsulfone and diphenyl sulfone; and a compound having a urea skeleton inwhich a hydrogen atom bonded to the nitrogen atom may be substitutedsuch as 1,3-dimethyl-2-imidazolidinone and1,3-diethyl-2-imidazolidinone,

Among them, as the organic solvent, dimethylsulfoxide,dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, sulfolane,diphenylsulfone or 1,3-dimethyl-2-imidazolidinone is preferable, anddimethylsulfoxide, dimethylformamide, dimethylacetamide,N-methyl-2-pyrrolidone, sulfolane or 1,3-dimethyl-2-imidazolidinone ismore preferable.

One of these organic solvents may be used alone or two or more of themmay be used in combination.

[Polymerization]

In the method for producing an aromatic polysulfone, as a first stage,an aromatic dihalogenosulfone compound and an aromatic dihydroxycompound are dissolved in an organic solvent. As a second stage, analkali metal salt of carbonic acid is added to the solution obtained inthe first stage to subject the aromatic dihalogenosulfone compound andthe aromatic dihydroxy compound to a polycondensation reaction. As athird age, an unreacted base, by-products (alkali halide when an alkalimetal salt is used as a base) and the is solvent are reduced front thereaction mixture obtained in the second stage to obtain an aromaticpolysulfone.

The melting temperature in the first stage is preferably 40° C. or moreand 180° C. or less. Further, the reaction temperature of thepolycondensation in the second stage is preferably 180° C. or more and400° C. or less. If a side reaction does not occur, the higher thepolycondensation temperature, the faster the intended polycondensationprogresses, so that the degree of polymerization of the obtainedaromatic polysulfone increases. As a result, the reduced viscosity ofthe aromatic polysulfone tends to increase. However, in fact, as thepolycondensation temperature increases, side reactions similar to thosedescribed above are more likely to occur, and the degree ofpolymerization of the obtained aromatic polysulfone decreases.Therefore, also by taking the extent of these side reactions intoconsideration, its necessary to adjust the polycondensation temperature,so that an aromatic polysulfone, having a predetermined reducedviscosity can be obtained.

The blending ratio of the aromatic dihalogenosulfone compound withrespect to the aromatic dihydroxy compound is preferably 80 mol % ormore and 120 mol % or less, and more preferably 90 mol % or more and 110mol % or less.

The ratio of the alkali metal salt of carbonic acid used with respect tothe aromatic dihydroxy compound is, as the alkali metal, preferably 90mol % or more and 130 mol % or less, and more preferably 95 mol % ormore and 120 mol % or less.

If a side reaction does not occur, the higher the ratio of the alkalimetal salt of carbonic acid used, the faster the intendedpolycondensation progresses, so that the degree of polymerization of theobtained aromatic polysulfone increases. Asa result, the reducedviscosity of the aromatic polysulfone tends to increase.

However, in fact, as the ratio of the alkali metal salt of carbonic acidused increases, side reactions similar to those described above are morelikely to occur, and the degree of polymerization of the obtainedaromatic polysulfone decreases. Therefore, also by taking the extent ofthese side reactions into consideration, it is necessary to adjust theratio of the alkali metal salt of carbonic acid used, so that anaromatic polysulfone having a predetermined reduced viscosity can beobtained.

Usually, in the polycondensation in the second stage, the temperature isgradually raised to the reflux temperature of the organic solvent, whilereducing the amount of water generated as a by-product. After reachingthe reflux temperature of the organic solvent, it is preferable tofurther maintain the temperature for a predetermined time. Thepredetermined time is preferably 1 hour or more and 50 hours or less,and more preferably 2 hours or more and 30 hours or less. If a sidereaction does not occur, the longer the polycondensation time, the morethe intended polycondensation progresses, so that the degree ofpolymerization of the obtained aromatic polysulfone increases. As aresult, the reduced viscosity of the aromatic polysulfone tends toincrease. However, in fact, as the polycondensation time increases, sidereactions similar to those described above are allowed to proceed, andthe degree of polymerization of the obtained aromatic polysulfonedecreases.

Therefore, also by taking the extent of these side reactions intoconsideration, it is necessary to adjust the polycondensation time, sothat an aromatic polysulfone having a predetermined reduced viscositycan be obtained.

In order to obtain an aromatic polysulfone having at least one highlypolar functional group at its terminal, after the polymerizationreaction, the functional group at the terminal of the polymer may bereplaced by a compound having a highly polar functional group. Morespecifically, an aromatic polysulfone having at least one highly polarfunctional group at its terminal can be obtained by using a compoundhaving a functional group reactive with the aforementioned X¹, X² orphenolic hydroxyl group at the terminal of the polymer and a highlypolar functional group (hereinafter may be referred to as an end cappingagent), and reacting with the obtained polymer.

This reaction can be easily carried out by adding an end capping agentat the time when the polymerization reaction is completed. Specificexamples of the end capping agent include 4-hydroxybenzesulfonic acid,3-hydroxybenzenesulfonic acid, (4-hydroxyphenyl) phosphoric acid andalkali metal salts thereof.

In the third stage, first, from the reaction mixture obtained in thesecond stage, the unreacted alkali metal salt of carbonic acid and analkali halide generated as a by-product are reduced through filtration,extraction, centrifugation or the like, thereby obtaining a solution inwhich an aromatic polysulfone is dissolved in an organic solventthereinafter may be referred to as “aromatic polysulfone solution” insome cases). Then, by reducing the organic solvent from the aromaticpolysulfone solution, an aromatic polysulfone is obtained.

As a method for reducing the organic solvent from the aromaticpolysulfone solution, for example, a method of directly reducing theorganic solvent from the aromatic polysulfone solution under reducedpressure or increased pressure can be mentioned. In addition, as anothermethod, a method of mixing an aromatic polysulfone solution and a poorsolvent of aromatic polysulfone to precipitate the aromatic polysulfoneand reducing the organic solvent by filtration, centrifugation or thelike can be mentioned. In the present embodiment, if necessary, theprecipitated aromatic polysulfone may be repeatedly washed with a poorsot vent of aromatic polysulfone.

The aromatic polysulfone obtained in this manner is a mixture in whichan aromatic polysulfone having a highly polar functional group and anaromatic polysulfone having no highly polar functional group are mixedin a predetermined ratio.

In the present embodiment, by performing a predetermined operation onthe mixture, the ratio of the aromatic polysulfone having a highly polarfunctional group with respect to the combined total of all the aromaticpolysulfones (that is, the content ratio of the aromatic polysulfonehaving a highly polar functional group with respect to the total mass ofaromatic polysulfones) can be adjusted.

Hereinafter, an example of a method for adjusting the content ratio ofthe aromatic polysulfone having a highly polar functional group will bedescribed in detail.

First, a mixture of aromatic polysulfones and a predetermined solventare mixed. As the predetermined solvent, a solvent which is more likelyto dissolve an aromatic polysulfone having no highly polar functionalgroup than an aromatic polysulfone having a highly polar functionalgroup is used. As such a solvent, dichloromethane, chloroform and thelike can be mentioned. Among them, it is preferable to usedichloromethane because of the large solubility difference between thesearomatic polysulfones.

When a mixture of aromatic polysulfones and a predetermined solvent aremixed, the aromatic polysulfone having no highly polar functional groupis eluted from the mixture of aromatic polysulfones toward thepredetermined solvent present around the mixture of aromaticpolysulfones. At this time, although the aromatic polysulfone having ahighly polar functional group is also eluted, since its elution amountis smaller than that of the aromatic polysulfone having no highly polarfunctional group, in a solution ((a portion of aromaticpolysulfones)+(predetermined solvent)), the ratio of the aromaticpolysulfone having a highly polar functional group is low. On the otherhand, in the solid remaining without being doted ((the remainder of thearomatic polysulfones)+(a all amount of the predetermined solvent)),since the ratio of the aromatic polysulfone having no highly polarfunctional group is reduced, as a result, the ratio of the aromaticpolysulfone having a highly polar functional group is increased.

Subsequently, this mixture ((mixture of aromaticpolysulfones)+(predetermined solvent)) is separated into a solid and asolution by filtration, centrifugation or the like. By reducing thepredetermined solvent respectively from the solid and the solution, itcan be separated into a component containing a large amount of aromaticpolysulfone having a highly polar functional group and a componentcontaining a small amount of aromatic polysulfone having a highly polarfunctional group. As a method for reducing the predetermined solvent,the method exemplified as the method for reducing organic solvent in thethird stage can be mentioned.

Such an operation may be repeated until the aromatic polysulfone havinga highly polar functional group reaches a desired ratio. Further, it isalso possible to prepare two or more types of aromatic polysulfonesdiffering in the ratio of aromatic polysulfone having a highly polarfunctional group and blend them appropriately in accordance with theintended ratio of the aromatic polysulfone having a highly polarfunctional group.

The ratio of the aromatic polysulfone having a highly polar functionalgroup contained in the aromatic polysulfone of the present embodimentcan be adjusted in this manner.

<Aromatic Polysulfone Composition>

The aromatic polysulfone composition of the present embodimentpreferably contains the above-mentioned aromatic polysulfone and alsocontains a filler. In addition, it may further contain a resin otherthan the aromatic polysulfone.

In the aromatic polysulfone composition of the present embodiment, thecontent of the aromatic polysulfone is preferably from 20 to 95% by masswith respect to the total mass of the aromatic polysulfone composition.

Examples of the filler in the present embodiment include a fibrousfiller, a plate filler, a spherical filler, a powder filler, anirregularly shaped filler and a whisker.

Examples of the fibrous filler include glass fibers, PAN-based carbonfibers, pitch-based carbon fibers, silica alumina fibers, silica fibers,alumina fibers, other ceramic fibers, liquid crystal polymer (sometimesabbreviated as LCP) fibers, aramid fibers and polyethylene fibers.Further, whiskers such as wollastonite and potassium titanate fibers canalso be mentioned.

Examples of the plate filler include talc, mica, graphite andwollastonite.

Examples of the spherical filler include glass beads and glass balloons.

Examples of the powder filler include calcium carbonate, dolomite, claybarium sulfate, titanium oxide, carbon black, conductive carbon and fineparticulate silica.

Examples of the irregularly shaped filler include glass flakes andmodified cross-section Mass fibers.

The content of the filler is preferably from 0 to 250 parts by mass,more preferably from 0 to 70 parts by mass, still more preferably from 0to 50 parts by mass, and particularly preferably from 0 to 25 parts bymass, with respect to 100 parts by mass of the aromatic polysulfone.

Examples of resins other than the aromatic polysulfone includepolyamides, polyesters, polyphenylene sulfides, polycarbonates,polyphenylene ethers, aromatic polyketones, polyether imides, phenolresins, epoxy resins, polyimide resins and modified products thereof.

The content of the resin other than the aromatic polysulfone ispreferably from 5 to 2,000 parts by mass, more preferably from 10 to1,000 parts by mass, and still more preferably from 20 to 500 parts bymass, with respect to 100 parts by mass of the aromatic polysulfone.

[Organic Solvent]

The aromatic polysulfone composition of the present embodiment mayfurther contain an organic solvent. It should be noted that the organicsolvent may be added later when preparing the aromatic polysulfonecomposition, or may be contained in advance in the aromaticpolysulfonic. As such an organic solvent, the same organic solvents asthose exemplified in the production method of the present embodiment canbe used.

The content of e organic solvent s preferably from 0 to 1 part by masswith respect to 100 parts by mass of the aromatic polysulfone.

[Other Components]

The aromatic polysulfone composition of the present embodiment maycontain various materials as necessary, as long as the effects of thepresent invention are not impaired. Examples of such materials includecoloring components, lubricants, various surfactants, antioxidants, heatstabilizers, various other stabilizers, ultraviolet absorbers andantistatic agents.

The content of other components is preferably from 0 to 1 part by masswith respect to 100 parts by mass of the aromatic polysulfone.

As one aspect, the aromatic polysulfone composition of the presentembodiment includes

the above-mentioned aromatic polysulfone, and

at least one component selected from the group consisting of a filler, aresin other than the aromatic polysulfone, an organic solvent, and othercomponents.

According to the present embodiment, an aromatic polysulfone excellentin releasability and an aromatic polysulfone composition containing thearomatic polysulfone are provided.

Another aspect of the aromatic polysulfone of the present embodiment is

an aromatic polysulfone including an aromatic polysulfone having atleast one highly polar functional group at its terminal,

wherein the aforementioned aromatic polysulfone includes

a repeating unit represented by the above formula (1), preferably arepeating unit obtained, by a polycondensation reaction ofbis(4-chlorophenyl) sulfone with bis(4-hydroxyphenyl) sulfone; and

an area of a signal attributed to the aforementioned aromaticpolysulfone having a highly polar functional group with respect to atotal area of all signals attributed to the aforementioned aromaticpolysulfone in a chromatogram obtained by measurement through a gelpermeation chromatography method under the following conditions is 0.1%or more and 11% or less, or may be 8% or more and 11% or less.

[Conditions]

Sample injection volume: 5 μL

Column: “Shodex KF-803” manufactured by Showa Denko K.K.

Column temperature: 40° C.

Eluent: N,N-dimethylformamide

Eluent flow rate: 0.5 mL/min

Detector: ultraviolet-visible spectrophotometer (UV)

Detection wavelength: 277 nm

The aforementioned aromatic polysulfone is preferably an aromaticpolysulfone having a peel strength of 0.66 N/cm less at 260° C. and apeel strength of not more than 1.51 N/cm² at 280° C. when the peelstrength is measured under predetermined conditions.

EXAMPLES

Hereinafter, the present invention will be described in more detail withreference to examples and comparative examples, but the presentinvention is not limited thereto.

It should be noted that in these examples, measurement and evaluation ofaromatic polysulfones were carried out under the following conditions.

<Measurement of Mn and Mw Values of Aromatic Polysulfones, andCalculation of Mw/Mn Value>

The weight average molecular weight (Mw), number average molecularweight (Mn) and polydispersity (Mw/Mn) of aromatic polysulfones weredetermined by GPC measurement. It should be noted that both Mn and Mwvalues were measured twice, and the average values thereof weredetermined as Mn and Mw, respectively, to obtain the average value ofMw/Mn.

[Measurement Conditions]

Sample: 0.002 g of aromatic polysulfone was added to 1 mL of anN,N-dimethylformamide solution containing 10 mM lithium bromide

Sample injection volume: 100 μL

Column (stationary phase): Two columns of “TSKgel GMHHR-H” (7.8 mmφ×300mm) manufactured by Tosoh Corporation were connected in series

Column temperature: 40° C.

Eluent (mobile phase): N,N-dimethylformamide containing 10 mM lithiumbromide

Eluent flow rate: 0.8 mL/min

Detector: differential refractive index meter (RI)+light scatteringphotometer (LS)

Standard reagent: polystyrene

Molecular weight calculation method: absolute molecular weight wascalculated from measurement result of light scattering photometer (LS)

<Measurement of Content of Aromatic Polysulfone having Highly PolarFunctional Group (Content Measurement)>

The ratio of the aromatic polysulfone having a highly polar functionalgroup with respect to the combined total of all the aromaticpolysulfones (that is, the content ratio of the aromatic polysulfonehaving a highly polar functional group with respect to the total mass ofaromatic polysulfones) was obtained by dividing the area of the signalattributed to the aromatic polysulfone having a highly polar functionalgroup by the total area of signals attributed to the aromaticpolysulfones in the GPC measurement.

[Measurement Conditions]

Apparatus: “Nexera X2” manufactured by Shimadzu Corporation

Sample: 0.001 g of aromatic polysulfone was added to 1 mL of anN,N-dimethylformamide solution

Sample injection volume: 5 μL

Column (stationary phase): “Shodex KF-803” (8.0 mmφ×300 mm) manufacturedby Showa Denko K.K.

Column temperature: 40° C.

Eluent (mobile phase): N,N-dimethylformamide

Eluent flow rate: 0.5 mL/min

Detector: ultraviolet-visible spectrophotometer (UV)

Detection wavelength: 277 nm

[Analysis Conditions]

Software: “LabSolutions” manufactured by Shimadzu Corporation

Width (W): 70 seconds

Slope (S): 1,000 uV/min

Drift (D): 0 uV/min

Minimum area/height (M): 1,000 counts

Analysis start time: 0 minutes

Analysis end time: 22 minutes

<Measurement of the Number of Phenolic Hydroxyl Groups in AromaticPolysulfone>

The number (A) of phenolic hydroxyl groups per 100 repeating unitsrepresented by the formula (1) was determined by ¹H-NMR measurement.More specifically, in the ¹H-NMR measurement, it was calculated based onthe following formula (S1) using an area (x) of a signal attributed tofour hydrogen atoms bonded to the phenol group in the repeating unit (1)and an area (y) of a signal attributed to two hydrogen atomsrespectively bonded to the carbon atom two atoms away from the phenolichydroxyl group.A=(y×100/x)×2(S1)

It should be noted that in the spectrum obtained when measured under thefollowing conditions, the signal attributed to the four hydrogen atomsbonded to the phenol group in the repeating unit (1) was observed from6.5 to 6.95 ppm. In addition, the signal attributed to each of the twohydrogen atoms bonded to the carbon atom atoms away from the phenolichydroxyl group was observed from 7.2 to 7.3 ppm.

[Measurement Conditions]

Apparatus: “Varian NMR System PS400WB” manufactured by Varian Inc.

Magnetic field strength: 9.4 T (400 MHz)

Probe: “'Varian 400 DB AutoX WB Probe” (5 mm) manufactured by VarianInc.

Measurement method: single pulse method

Measurement temperature: 50° C.

Measurement solvent: deuterated dimethylsulfoxide (containing TMS)

Latency: 10 seconds

Pulse irradiation time: 11.9 μs (90° pulse)

Number of integrations: 64 times

External standard: TMS (0 ppm)

<Production of Aromatic Polysulfone>

Production Example 1

85.46 parts by mass of bis(4-chlorophenyl) sulfone, 75.08 parts by massof bis(4-hydroxyphenyl) sulfone, 43.54 parts by mass of potassiumcarbonate and 165 parts by mass of N-methyl-2-pyrrolidone (hereinaftersometimes referred to as “NMP”) were mixed and reacted at 190° C. for 6hours in a polymerization vessel equipped with a stirrer, a nitrogeninlet tube, a thermometer, and a condenser attached with a receiver atthe tip. Subsequently, the obtained reaction mixture solution wasdiluted with NMP and cooled to room temperature to precipitate unreactedpotassium carbonate and potassium chloride generated as a by-product. Byreducing the amount of these inorganic salts by filtration, an aromaticpolysulfone solution in which an aromatic polysulfone was dissolved inNMP was obtained. Furthermore, this solution was added dropwise intowater to precipitate the aromatic polysulfone, and unnecessary NMP seasreduced by filtration, thereby obtaining a precipitate. The obtainedprecipitate was repeatedly washed with water and dried by heating at150° C. to obtain an aromatic polysulfone.

In the above content measurement the obtained chromatogram is shown inFIG. 2. That is, FIG. 2 shows a chromatogram of Production Example 1obtained by the above content measurement. As a result of fractionationof the aromatic polysulfone having a highly polar functional group(component A) in the chromatogram shown in FIG. 2, followed by analysisby the MALDI method, it was found ha the highly polar functional groupwas sulfonic acid or sulfinic acid.

Example 1

1 part by mass of the aromatic polysulfone obtained in ProductionExample 1 and about 10 parts by mass of dichloromethane were mixed andshaken at room temperature and then allowed to stand for 1 hour. Afterstanding, the upper layer dissolved in dichloromethane was extracted toobtain a solution in which the aromatic polysulfone was dissolved.Dichloromethane was distilled off from this solution and dried, wherebyan aromatic polysulfone of Example 1 was obtained.

Comparative Example 1

The aromatic polysulfone of Production Example 1 was used as it was.

Mw and Mw/Mn values and the number (A) of phenolic hydroxyl groups per100 repeating units represented by the (1) of the aromatic polysulfonesof the examples and comparative examples are shown in Table 1.

TABLE 1 Number of phenolic hydroxyl groups (groups/100 repeating units)Mw Mw/Mn Example 1 1.82 28,400 2.03 Comparative 2.44 30,700 1.86 Example1

Example 2

100 parts by mass of the aromatic polysulfone of Example 1 and 100 partsby mass of the aromatic polysulfone of Production Example 1 were mixedto obtain an aromatic polysulfone of Example 2. The ratio of thearomatic polysulfone having highly polar functional group calculatedfrom the mixing ratio in Example 1 and Production Example 1 is shown inTable 2.

Example 3

30 parts by mass of the aromatic polysulfone of Example 1 and 70 partsby mass of the aromatic polysulfone of Production Example 1 were mixedto obtain an aromatic polysulfone of Example 3. The ratio of thearomatic polysulfone having a highly polar functional group calculatedfrom the mixing ratio in Example 1 and Production Example 1 is shown inTable 2.

<Evaluation of Releasability of Aromatic Polysulfone>

15 parts by mass of the aromatic polysulfones of Examples 1 to 3 andComparative Example and 85 parts by mass of NMP were mixed in a heatingvessel and stirred at 60° C. for 2 hours to obtain a pale yellowaromatic polysulfone solution. The resultant was applied to one side ofa glass plate having a thickness of 3 mm using a film applicator andthen dried at 60° C. using a high temperature hot air dryer to form acoating film of an aromatic polysulfone. This coating film washeat-treated at 250° C. while causing nitrogen to flow, thereby formingan aromatic polysulfone film having a thickness of 30 μm on the glassplate. This film was peeled off from the glass plate to obtain anaromatic polysulfone

Subsequently, the aromatic polysulfone: film and a polyimide film(“Kapton 300H” manufactured by DuPont-Toray Co., Ltd.) were pressurebonded at 3 MPa and 260° C. or 280° C. for 30 minutes. Then, peelstrength was measured using Autograph, and releasability of the aromaticpolysulfone were evaluated. It should be noted that measurements weremade three times, and an average value therefrom was taken as the peelstrength of the aromatic polysulfone. Conditions for evaluating thereleasability using Autograph were as follows.

Tensile speed: 5 mm/min

Temperature: 23° C.

Humidity: 50%

The results of evaluation of releasability of the aromatic polysulfonesof Examples and Comparative Examples are shown in Table 2.

TABLE 2 Peel strength Ratio of aromatic (N/cm²) polysulfone havingPressure- Pressure- highly polar functional bonded bonded group (% bymass) at 260° C. at 280° C. Example 1 8 0.39 1.25 Example 2 10 0.52 0.96Example 3 11 0.66 1.51 Comparative 12 3.10 2.10 Example 1

As shown in Table 2, in the aromatic polysulfones of Examples 1 to 3,since the ratio of the aromatic polysulfone having a highly polarfunctional group with respect to the combined total of all the aromaticpolysulfones (that is, the content ratio of the aromatic polysulfonehaving a highly polar functional group with respect to the total mass ofaromatic polysulfones) was 11% by mass or less, the peel strength at260° C. and 280° C. was relatively low and the releasability wasexcellent.

On the other hand, in the aromatic polysulfone of Comparative Example 1,since the ratio of the aromatic polysulfone having a highly polarfunctional group with respect to the combined total of all the aromaticpolysulfones (that is, the content ratio of the aromatic polysulfonehaving a highly polar functional group with respect to the total mass ofaromatic polysulfones) was larger than 11% by mass, the peel strength at260° C. and 280° C. was relatively high and the releasability wasinferior.

INDUSTRIAL APPLICABILITY

According to the present invention, an aromatic polysulfone excellent inreleasability and an aromatic polysulfone composition containing thearomatic polysulfone can be provided, which is industrially useful.

The invention claimed is:
 1. An aromatic polysulfone comprising anaromatic polysulfone having at least one highly polar functional groupat its terminus, wherein the highly polar functional group is a polarfunctional group having an acid dissociation constant smaller than thatof a carboxyl group, and wherein in said aromatic polysulfone, an areaof a signal attributed to said aromatic polysulfone having a highlypolar functional group with respect to a total area of all signalsattributed to said aromatic polysulfone is 0.1% or more and 11% or lessin a chromatogram obtained through a gel permeation chromatographymethod.
 2. The aromatic polysulfone according to claim 1, whichcomprises a repeating unit represented by a formula (1),-Ph¹-SO₂-Ph²-O—  (1) wherein Ph¹ and Ph² each independently represent aphenylene group, and one or more hydrogen atoms in said phenylene groupmay be each independently substituted with an alkyl group, an aryl groupor a halogen atom.
 3. The aromatic polysulfone according to claim 2,which comprises 0.5 to 10 phenolic hydroxyl groups per 100 repeatingunits represented by said formula (1).
 4. An aromatic polysulfonecomposition comprising the aromatic polysulfone according to claim
 1. 5.The aromatic polysulfone composition according to claim 4, furthercomprising a filler.